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Working with Layer Comps
| Photoshop | For years, users of Photoshop have been clamoring for a savable History palette. This rings particularly true for designers who are often required to submit to their clients a bunch of variations on a particular concept. True, there are a handful of tricks for keeping different versions of images in one file, mostly having to do with creatively organizing layer sets and toggling visibilities. But it still hasn't been easy enough. Photoshop has never offered a reliable, quick method of saving different states of an image that can be recalled at the click of a button. Well, it is with a modicum of fanfare and a sprinkling of hullabaloo that I'm somewhat pleased to report a definitive solution — sort of. Photoshop CS offers the new Layer Comps palette (shown in Figure 12-38), which is designed to track certain aspects of an image and save their status at any given time. Essentially, it records snapshots of the Layers palette as individual states, or layer comps, which are saved with the image file on disk. So although we still don't have a savable History palette, layer comps come pretty darn close.  Figure 12-38: The impressive new Layer Comps palette enables you to leap through time without having to save up for that vintage DeLorean. |
The key to successfully working with layer comps is to be extremely conscious of what they are and aren't capable of tracking. A saved layer comp can store and recall information about the visibility, opacity, and blend modes of the layers in an image, as well as the position of each layer. Layer comps can also record whether or not styles are applied to each layer and the settings of those styles. What you need to keep in mind, however, is that layer comps don't even attempt to track any pixel changes to your images. This applies to painting, creating gradients, using the patch tool; any operation that alters the pixels (as well as text contents) of an image is not recorded in the Layer Comps palette. The palette will turn the other way and pretend you've done nothing at all.That said, layer comps can be a great and useful asset, especially when you're at the stage of assembling the final pieces into a composition. To save a layer comp, bring up Layer Comps palette by choosing Window Layer Comps or by clicking the Layer Comps tab in the Options bar's docking well (the palette is docked there by default). Next, click the new layer comp icon (labeled in Figure 12-38) to access the New Layer Comp dialog box, shown in Figure 12-39. Here, you set a name for your layer comp and any comments that might help you identify the state you're saving. This dialog box is also where you specify exactly what gets tracked by this layer comp. Three check boxes are available to you:
Figure 12-39: The New Layer Comp dialog box lets you specify exactly what type of layer data you want to track.
Visibility: Turn on this option to track the visibility of layers and layer masks.
Position: This option tracks the position of each separate layer in relation to the others. Again, it's important to note that position changes within layers — say, if you marquee a section of a layer and drag it over to a corner — cannot be restored through layer comps.
Appearance (Layer Style): This option saves all layer style attributes, including knockouts and effects, as well as the Opacity value and blend mode assigned to each layer.
Click OK to confirm your settings and, presto, you've created a new layer comp. You can tell that you're looking at a saved state of your image because the little icon in the left column of the Layer Comps palette sits alongside your new layer comp, as shown in Figure 12-40. As soon as you make any layer-comp-friendly changes to your image, such as moving a layer or adjusting its opacity, the icon will snap back to the topmost layer comp, known as the Last Document State. This means that trackable changes have been made to the image since your last saved layer comp. You can save this new state as another layer comp, if you want, and continue working. To return to a saved state, simply click in the space to the left of the layer comp.
Figure 12-40: Nearly all the functions available to you in the Layer Comps palette menu can be accessed from icons in the palette.
Working with the Layer Comps palette is pretty easy once you get used to it, but there are a few things you should know:
Use the left- and right-pointing arrowheads at the bottom of the palette to cycle through your various layer comps. Click the right-pointing arrowhead to view the next saved layer comp down the list and click the left-pointing arrowhead to view the previous layer comp. To cycle through only specific comps, Ctrl-click (z -click on the Mac) or Shift-click to select them and then click the arrowheads.
To the right of the arrowhead icons is the update layer comp icon (it's the one with two arrows that form a circle). Click this icon to assign changes to an existing selected layer comp. The icon in the left column of the palette leaps over to whatever layer comp you've selected and the current state of the Layers palette is applied to this layer comp.
To delete a layer comp, simply select it and click the trash can icon, just as you would to delete a layer in the Layers palette. Here, you also have the added benefit of being able to select and drag multiple layer comps to the trash icon at once.
You can always return the image to its most recent unsaved layer state by clicking in the space next to the Last Document State item in the palette.
All of these options can also be accessed from the Layer Comps palette menu, as shown in Figure 12-40. The palette menu also lets you duplicate any selected layer comp or access its options without having to double-click it.
| Caution | Fragile creatures that they are, layer comps have a tendency to break down every once in a while. Luckily, though, they're pretty good at letting you know when they're unhappy. Whenever you make a change that will throw any of your layer comps out of whack — such as merging layers or converting a layer into a background — the affected comps will display a little triangle with an exclamation point. You can either undo the destructive move or click one of the triangle icons, in which case you'll be presented with a warning explaining exactly how you've betrayed the layer comp. From this warning, you have the option of "clearing" the layer comp, which is a way of updating the comp to account for the changes you've made. Right-click (Control-click on the Mac) any of the triangles and choose Clear Layer Comp Warning to clear that particular layer comp, or choose Clear All Layer Comp Warnings to clear all the layer comps without having to wrangle with the warnings for each. |
